One conventional form of product dispenser for spices, condiments and other similar dry particulate materials includes a container with a round server lid screwed onto its neck. The round server lid is often known and referred to as a "closure" by those skilled in the art. In the product dispensing art, round closures include one or more dispensing ports for such purposes as sifting, pouring or spooning spices or other condiments from the container. These closures also include one or more vertically movable flaps that snap close over the dispensing ports to keep the product in the container. In this particular server lid closure art it is conventional that the round closure is screwed onto the neck of a container. One reason for this convention is that a separate plastic or foil seal strip is often applied over the entire open end of the container. The plastic or foil seal strip serves the purpose of maintaining the freshness or shelf-life of the product inside the container. Prior to first use, the closure is removed by unscrewing it, the plastic or foil seal strip is removed, then the closure replaced. An exemplary product dispenser including a closure as described above is generally disclosed in VerWeyst et al., U.S. Pat. No. 4,898,292, the disclosure of which is hereby incorporated by reference in its entirety.
Round closures as disclosed in the '292 patent to VerWeyst et al. work very well and are highly practical for the consuming public. However, as is recognized by the '292 patent to VerWeyst et al., round screw-on closures present certain difficulties from an automated assembly standpoint. In particular, when the closure is screwed on the container, the resilient plastic material in the closure tends to deflect or shift after the closure engages the top lip of the container towards the end of the screwing motion. Occasionally too much torque is applied (a condition known as over-torquing) which results in the hinged flaps undesirably popping open. The '292 patent to VerWeyst et al. discloses an improved locking arrangement to address this problem and better maintain the hinged flaps in the closed position during assembly. Although the locking arrangement taught by VerWeyst et al. reduces the number of open flaps occurring during assembly, an undesirable number of flaps still inevitably open during assembly operations even with this improvement. This specific locking arrangement also reduces the number of design options possible for the port configuration of the dispensing ports of the closure.